Ding is a dictionary lookup program for the X
Window system on Linux/Unix. It comes with a
German-English Dictionary with about 253,000
entries. It is based on Tk version >= 8.3 and uses
the agrep or egrep tools for searching. In
addition ding can also search in English
dictionaries using dict(1) and check spelling
using ispell(1). It has many configuration
options, such as search preferences, interface
language (English or German), and colors. It has
history and help functions and comes with useful
key and mouse bindings for quick and easy lookups.

MAPDAV (More Accurate Password Dictionary Attack Vector) is designed to use what is known about users via the /etc/passwd file on Unix/Linux systems to generate a dynamic dictionary of more accurate guesses as to what their possible password may be. It does this by mangling the user's username and user information in various user-specified ways to look for bad password protection practices.

Artha is a handy thesaurus based on WordNet with distinct features like global hot key look up, passive desktop notification, regular expression based search, etc. Artha may be used as a free open-source replacement/clone to the proprietary WordWeb Pro thesaurus (which is also based on WordNet) on Unix-like and Windows operating systems.

HogTrans provides an automatic word translation engine built on statistics of text translations used for free software. It basically provides an automatically created dictionary with multiple translations and example usages for each. HogTrans can import translations from standard GNU .mo-files.

Dictconv-cx is a dictionary converter that is a stripped down and expanded version of dictconv. It removes support for the DICT dictionary, stardict, as other tools such as makedict handle it well, and adds support for UTF-8 encoding, keywords longer than 255 characters, 82,000+ character length in definitions, and other changes.